Munch,
Firstly, the UAE is part of ICAO so the licence your friend gets is internationally recognised.
Secondly, regarding conversion to the FAA, I think you can get a licence over the counter based on your UAE one. To get an unrestriced FAA PPL (if I remember correctly), you need to do the written exam and a Flight test. (This was a pre 9-11 though, so things may have changed!) Regarding the CAA, it used to be a case of doing a airlaw written, a R/T written and a aeromedical written (or whatever it was called) and then a practical R/T exam. (NO GFT REQ!) Now with the JAA, I have no idea.
Finally, there are flying schools in Dubai, Fujairah and Umm Al Quain. All charge different rates per hour and all operate different aircraft. I suggest you try their web sites to find out how much they charge per hour. (I believe the average is around 500UAE Dirhams per hour). Without advertising their web sites, the names of the relevant orgs are, Fujairah Aviation and Emirates Flying School (Dubai).
One more thing, there was a thread on this forum not so long ago asking the same questions, so a quick search may well give you further info.
F-S